The effectiveness of proton beam therapy for liver metastatic recurrence in gastric cancer patients.

OBJECTIVE: The purpose of this cross-sectional study was to evaluate the efficacy and safety of proton beam therapy for liver metastatic recurrence in gastric cancer patients. METHODS: Consecutive patients who underwent proton beam therapy from 2010 to 2015 were isolated from our institutional database. Patients with extrahepatic metastatic lesions were excluded. Seven patients were enrolled. The median diameter of target lesions was 31 mm (13-68 mm). The most frequent dosage was 72.6 Gy equivalent in 22 fractions. The effectiveness was assessed based on the local control, overall survival and progression-free survival rates. The local control, overall survival and progression-free survival rates were calculated using the Kaplan-Meier method. Adverse events were described according to the patients' medical records. RESULTS: The median follow-up period was 41.7 months (20.7-66.3 months). The 3-year local control, overall survival and progression-free survival rates were 85.7, 68.6 and 43%, respectively. All patients completed proton beam therapy without interruption. No grade ≥3 adverse events were observed. CONCLUSIONS: Proton beam therapy might be a treatment option for patients with liver metastasis of gastric cancer.